A5043220337- Advancements in Battery Materials
- Advanced Battery Materials and Technologies
- Gamma-ray bursts and supernovae
- Advanced Battery Technologies Research
- Stellar, planetary, and galactic studies
- Astrophysics and Cosmic Phenomena
- Astrophysical Phenomena and Observations
- Advanced NMR Techniques and Applications
- Advanced MRI Techniques and Applications
- Extraction and Separation Processes
- NMR spectroscopy and applications
- Pulsars and Gravitational Waves Research
- Polyoxometalates: Synthesis and Applications
- Recycling and Waste Management Techniques
- Galaxies: Formation, Evolution, Phenomena
- Advanced Polymer Synthesis and Characterization
- Atomic and Subatomic Physics Research
- Advanced Optical Network Technologies
- Semiconductor Lasers and Optical Devices
- Astronomy and Astrophysical Research
Columbia University
2020-2024
University of California, Berkeley
2018-2022
The high-voltage LiNi0.5Mn1.5O4 (LNMO) spinel cathode material offers high energy density storage capabilities without the use of costly Co that is prevalent in other Li-ion battery chemistries (e.g., LiNixMnyCozO2 (NMC)). Unfortunately, LNMO-containing batteries suffer from poor cycling performance because intrinsically coupled processes electrolyte oxidation and transition metal dissolution occurs at voltage. In this work, we operando electron paramagnetic resonance (EPR) nuclear magnetic...
The role of the cathode–electrolyte interphase (CEI) on battery performance has been historically overlooked due to anodic stability carbonate-based electrolytes used in Li-ion batteries. Yet, over past few decades, degradation device lifetime attributed cathode surface reactivity, ion transport at cathode/electrolyte interface, and structural transformations that occur surface. In this review, we highlight recent progress analytical techniques have facilitated these insights elucidated not...
We present BVRI and unfiltered light curves of 93 Type Ia supernovae (SNe Ia) from the Lick Observatory Supernova Search (LOSS) follow-up program conducted between 2005 2018. Our sample consists 78 spectroscopically normal SNe Ia, with remainder divided distinct subclasses (three SN 1991bg-like, three 1991T-like, four Iax, two peculiar, super-Chandrasekhar events), has a median redshift 0.0192. The in our have coverage 16 photometric epochs at cadence 5.4 days, first observed epoch is ~4.6...
In this work, BV RI light curves of 55 Type II supernovae (SNe II) from the Lick Observatory Supernova Search program obtained with Katzman Automatic Imaging Telescope and 1 m Nickel telescope 2006 to 2018 are presented. Additionally, more than 150 spectra gathered 3 Shane published. We conduct an analyse peak absolute magnitudes, decline rates, time durations different phases colour curves. Typically, our sampled a median cadence 5.5 days for total 5093 photometric points. average V-band...
Hydrogen-poor superluminous supernovae (SLSNe-I) have been predominantly found in low-metallicity, star-forming dwarf galaxies. Here we identify Gaia17biu/SN 2017egm as an SLSN-I occurring a "normal" spiral galaxy (NGC 3191) terms of stellar mass (several times 10^10 M_sun) and metallicity (roughly Solar). At redshift z=0.031, Gaia17biu is also the lowest to date, absence larger population SLSNe-I galaxies similar suggests that likely less important production than previously believed. With...
The advent of covalent adaptable networks (CANs) through the incorporation dynamic bonds has led to unprecedented properties macromolecular systems, which can be engineered at molecular level. Among various types stimuli that used trigger chemical changes within polymer networks, light stands out for its remote and spatiotemporal control under ambient conditions. However, most examples photoactive CANs need transparent they exhibit slow response, side reactions, limited penetration. In this...
We present observations of the extremely luminous but ambiguous nuclear transient (ANT) ASASSN-17jz, spanning roughly 1200 days object's evolution. ASASSN-17jz was discovered by All-Sky Automated Survey for Supernovae (ASAS-SN) in galaxy SDSS J171955.84+414049.4 on UT 2017 July 27 at a redshift $z=0.1641$. The peaked an absolute $B$-band magnitude $M_{B,{\rm peak}}=-22.81$, corresponding to bolometric luminosity $L_{\rm bol,peak}=8.3\times10^{44}$~erg~s$^{-1}$, and exhibited late-time...
Abstract We present extensive optical photometric and spectroscopic observations, from 4 to 482 days after explosion, of the Type II-plateau (II-P) supernova (SN) 2017eaw in NGC 6946. SN is a normal II-P intermediate properties between, for example, 1999em 2012aw more luminous 2004et, also have determined that extinction primarily due Galactic foreground site metallicity likely subsolar. independently confirmed tip-of-the-red-giant-branch (TRGB) distance 6946 7.73 ± 0.78 Mpc. The distances...
The high specific capacities of Ni-rich transition-metal oxides have garnered immense interest for improving the energy density Li-ion batteries (LIBs). Despite potential these materials, cathodes suffer from interfacial instabilities that lead to crystallographic rearrangement active material surface as well formation a cathode electrolyte interphase (CEI) layer on composite during electrochemical cycling. While changes in structure can be detected with diffraction-based methods, probing...
Quantifying the tortuosity of porous lithium-ion electrodes is important for understanding rate capability cells and optimizing their design, particularly when designing high energy density such as those desired electric vehicles. However, quantifying may be difficult, results often disagree with commonly used Bruggeman relation. Here, we discuss observation that PVDF binder, a polymer to mechanically hold electrode together, has direct effect on NMC111 cathodes. Using pseudo-two-dimensional...
Performance decline in Li-excess cathodes is generally attributed to structural degradation at the electrode-electrolyte interphase, including transition metal migration into lithium layer and oxygen evolution electrolyte. Reactions between these new surface structures and/or reactive species electrolyte can lead formation of a cathode interphase (CEI) on electrode, though link CEI composition performance materials not well understood. To bridge this gap understanding, we use solid-state...
We present BVRI and unfiltered Clear light curves of 70 stripped-envelope supernovae (SESNe), observed between 2003 2020, from the Lick Observatory Supernova Search (LOSS) follow-up program. Our SESN sample consists 19 spectroscopically normal SNe~Ib, two peculiar SNe Ib, six SN Ibn, 14 Ic, one ten Ic-BL, 15 IIb, ambiguous IIb/Ib/c, superluminous SNe. photometry has (on a per-SN basis) mean coverage 81 photometric points (median 58 points) cadence 3.6d 1.2d). From our full sample, subset 38...
The high-voltage LiNi0.5Mn1.5O4 (LNMO) spinel cathode material offers high energy density storage capabilities without the use of costly Co that is prevalent in other Li ion battery chemistries (e.g., LiNixMnyCozO2 (NMC)). Unfortunately, LNMO-containing batteries suffer from poor cycling performance due intrinsically coupled processes electrolyte oxidation and transition metal dissolution occurs at voltage. In this work, we operando electron paramagnetic resonance (EPR) spectroscopy nuclear...
A transient in the Local Group dwarf irregular galaxy NGC 6822 (Barnard's Galaxy) was discovered on 2017 August 2 and is only second classical nova that galaxy. We conducted optical, near-ultraviolet, X-ray follow-up observations of eruption, results which we present here. This 'very fast' had a peak $V$-band magnitude range $-7.41>M_V>-8.33$ mag, with decline times $t_{2,V} = 8.1 \pm 0.2$ d $t_{3,V} 15.2 0.3$ d. The early- late-time spectra are consistent an Fe II spectral class. H$\alpha$...
Localized high concentration electrolytes (LHCEs) are a promising class of to enable stable cycling the lithium metal anode. Here, we report use operando nuclear magnetic resonance (NMR) spectroscopy observe electrolyte decomposition during Li stripping/plating and identify influence individual components in LHCEs on battery performance. Data from 19F solution NMR indicates that both bis(fluorosulfonyl)imide (FSI–) salt bis(2,2,2-trifluoroethyl)ether (BTFE) diluent molecules play key role...
The high specific capacities of Ni-rich transition metal oxides have garnered immense interest for improving the energy density Li-ion batteries (LIBs). Despite potential these materials, cathodes suffer from interfacial instabilities that lead to crystallographic rearrangement active material surface as well formation a cathode electrolyte interphase (CEI) layer on composite during electrochemical cycling. While changes in structure can be detected with diffraction-based methods, probing...
The high specific capacities of Ni-rich transition metal oxides have garnered immense interest for improving the energy density Li-ion batteries (LIBs). Despite potential these materials, cathodes suffer from interfacial instabilities that lead to crystallographic rearrangement active material surface as well formation a cathode electrolyte interphase (CEI) layer on composite during electrochemical cycling. While changes in structure can be detected with diffraction-based methods, probing...
Localized high concentration electrolytes (LHCEs) are a promising class of to enable stable cycling the lithium metal anode. Here, we report use operando nuclear magnetic resonance (NMR) spectroscopy observe electrolyte decomposition during Li stripping/plating and identify influence individual components in LHCEs on battery performance. Data from 19F solution NMR indicates that both bis(fluorosulfonyl)imide (FSI–) salt bis(2,2,2-trifluoroethyl)ether (BTFE) diluent molecules play key role...